Surgical Eye Disease Flashcards
Bovine ocular squamous cell carcinoma is also known as what?
Cancer eye
What are 3 examples of squamous cell tumors?
- Plaques and keratomas
- Papillomas
- Squamous cell carcinomas
What is the most common eye tumor seen with cattle?
Bovine ocular squamous cell carcinoma
In what parts of the world is “cancer eye” seen?
Occurs throughout the world.
What age group of cattle is most commonly affected by “cancer eye”?
Older cattle
What are 3 examples of common bovine tumors?
- Ocular squamous cell carcinoma
- Bovine leukosis
- Adenocarcinoma of the uterus
What percentage of squamous cell carcinoma cases in cattle metastasize?
10%
What type of tumor is locally invasive?
Squamous cell carcinoma
What are 4 contributing factors for squamous cell carcinoma development in cattle?
- Genetic (Hereford)
- UV light
- Increased altitude
- Decreased latitude
Squamous cell carcinomas are most common in what breed of cattle?
Herefords
Lack of what can predispose cattle to squamous cell carcinoma of the eye?
Periocular pigmentation
High levels of what can predispose cattle to squamous cell carcinoma of the eye?
Sunlight
What are 7 problems that cancer eye can cause?
- Causes pain
- Stops eye from closing properly
- Becomes infected
- Interferes with growing
- Interferes with normal behavior
- Leads to loss of condition
- Eventual death
Cancer eye can cause economic loss in cattle in what 5 ways?
- Loss of condition
- Condemnation of the carcass
- Orphaning of the calves
- Treatment
- Death
What are 3 ways to diagnose cancer eye in cattle?
- Clinical signs
- Histopathology
- Cytology
What are 2 questions that should be asked when weighing the risks vs benefits of surgery for cancer eye in cattle?
- Is it cost effective?
- Is it spreading systematically?
What are 6 examples of forms of treatments for squamous cell carcinomas in cattle?
- Excisional surgery
- Cryotherapy
- Hyperthermia
- Radiation
- Immunotherapy
- Combination of the above
What are 3 forms of restraint that can be used for squamous cell carcinoma treatment?
- Squeeze chute
- Secure restraint of the head
- Xylazine
What is something that is typically necessary for horses with the treatment of squamous cell carcinoma of the eye?
General anesthesia
When there is superficial bulbar involvement with squamous cell carcinoma, what are 4 components to include?
- Auriculopalpebral nerve block
- Topical anesthesia
- Keratectomy
- Conjunctival resection
What is an example of a topical anesthetic that can be used directly on the cornea with squamous cell carcinoma?
Lidocaine
What can be used to immobilize the globe of an eye?
Spoon
What type of keratectomy can be used with some forms of squamous cell carcinoma?
Superficial keratectomy
What are 2 types of drugs that can be given post-op excision of a squamous cell carcinoma tumor?
- Antibiotics
- Corticosteroids
Hyperthermia can be used as a treatment on what size tumor?
Small circumscribed tumor
What is used to create the increased temperature for hyperthermia treatment?
Radio frequency
Malignant cells are sensitive to what temperature range?
41-45 C
What is the typical temperature reached with hyperthermia treatment?
For how long?
- 50 C
- 30-60 seconds
What other form of treatment can be combined with hyperthermia?
Surgical resection
How does hyperthermia affect the tumor?
Blood supply to tumor gets destroyed so the tumor becomes necrotic.
What are 2 colors a tumor can turn after hyperthermia treatment?
- Red
- Blue
How long does it usually take for a tumor to slough off after being treated with hyperthermia?
3 days
What might be seen on the skin once a tumor has been sloughed off after hyperthermia?
Dark red surface
Is cryosurgery for squamous cell carcinoma of the eye usually done under anesthesia?
Yes
What are 3 examples of blocks that can be used with cryosurgery?
- Local
- Retrobulbar
- Peterson block
Cryosurgery can be used on tumors less than what size?
50 mm
What is the best cryosurgery technique to use?
Double freeze-thaw cycle
What substance is often used for cryosurgery?
Liquid nitrogen
What effect does cryosurgery have on the tumor?
Necrosis
What temperature is the tumor frozen to with cryosurgery?
-25 C
What border of normal tissue around the tumor should also be frozen with cryosurgery?
0.2 - 0.4 cm
When removing tumors on or near the eyelid, one has to be careful not to do what?
Do not leave the eye exposed.
What is the preferred plastic surgery technique with eyelids?
H-plasty/Modified H-plasty
What should be included in the corners of the modified H-plasty to prevent dog ears or puckering from forming?
Triangles
What are two types of skin patterns that can be used to appose the skin after an eyelid H-plasty/modified H-plasty?
- Simple interrupted
- Cruciate
What can be done to reduce swelling after an eyelid modified H-plasty is performed?
Hot-packing
Removal of the intra-ocular contents while preserving the cornea and sclera is known as what?
Evisceration
What can be placed after an evisceration has been performed?
An inta-scleral silicone prosthesis
Removal of the globe, conjunctiva and nictitating membrane is known as what?
Enucleation
Removal of the entire orbital content is known as what?
Exenteration
What type of removal is often used for malignant tumors?
Exenteration
If deep layers of the globe are affected, what block and method are used?
- Peterson block
- Orbital exenteration
If exenteration is being considered, you have to make sure that what is not affected?
Underlying bone
What type of needle can be used to perform a four point retrobulbar block?
Curved spinal needle
What are two vessels that are difficult to ligate with an exenteration?
- Optic artery
- Optic vein
What is a type of clamp that can be used on the optic pedicle?
Stelle vessel pattern clamp
What can be used to pack the orbit?
Absorbable gelatin sponge
Pressure from what forming can help to control the bleeding after eye removal?
Hematoma
What are two ways to try to prevent squamous cell carcinoma around the eye in cattle?
- Close observation 3x year
- Tattooing of non-pigmented lids
What can be used to treat pink eye in cattle?
What is this composed of?
- Subconjunctival injection
- Non-irritating 50/50 combo of penicillin and corticosteroid
What kind of effect does administering a high drug concentration in local tissues have?
Depot effect
Atropine can be used for what type of supportive therapy for pink eye?
Relieves discomfort
What do corticosteroids help reduce when used for pink eye?
Reduce inflammation
Are corticosteroids contraindicated with corneal ulcers in cattle?
No
Corticosteroids are not used for corneal ulcers in what species?
Horses
What percentage are the atropine ointment or drops used?
1%
What should be done to the periorbital hair before working on the eye?
How should this be done?
- It should be clipped
- Use scissors NOT clippers
What type of agents should not be used around the eye to clean it?
What are two that can be used?
- Detergents shouldn’t be used
- Eye wash and aqueous antibiotics
If suturing the third eyelid, what part should the needle be placed through?
How deep?
From which surface?
- In the cartilage of the 3rd eyelid
- Partial thickness
- Palpebral surface
Where is the 3rd eyelid sutured to with a third eyelid flap?
Upper eyelid
What type of suture pattern is used with a third eyelid flap?
How many are placed?
- Horizontal mattress
- 3
What is a good type of suture to use with a third eyelid flap?
Catgut suture
What is a temporary way to keep an eye closed?
Temporary tarsorrhaphy upper to lower eyelid
What is a condition that can lead to corneal ulceration or perforation?
Entropion
What are 4 possible treatments for entropion with cattle?
- Manual eversion of the eyelid
- Injection of 4 mL of saline close to lid margins
- Skin staple or horizontal mattress suture
- Skin removal techniques
What is an example of a skin removal technique that can be used to treat entropion?
Hotz-celsus
An eyelid laceration closure is performed in how many layers?
2 layers
